carnivore diet science researchFollowing up on last week’s big carnivore post, today I want to look at some of the main reasons people choose a carnivore diet in the first place.

There are those who just like meat a whole heckuva lot and don’t want to be bothered with vegetables, but I don’t think they represent the majority of the carnivore crowd. From what I can tell, most people come to the carnivore diet because they’re dealing with persistent health issues that aren’t being adequately resolved through conventional means. Maybe they’ve been trying something like Primal, paleo, or keto for a while, but there’s still room for improvement. Others are doing well but wish to see if they could achieve another level of awesomeness by doing something different or, dare I say, more extreme.

In these cases, carnivore is a sensible experiment for a number of reasons:

Carnivore diets combine the advantages of ketogenic and elimination diets, both of which are already popular for dealing with intractable health problems.

A nose-to-tail carnivorous diet is highly nutritious, providing bioavailable vitamins and minerals, plus plenty of protein, that the body needs.

If carnivore puts you in ketosis—and it almost certainly will—you get the anti-inflammatory benefits of ketones, plus mitochondrial biogenesis, increased fat-burning, appetite suppression, and more.

By removing potentially problematic plant foods, carnivore diets contain little or no:

  • FODMAPs
  • Oxalates
  • Lectins
  • Phytates
  • Glycoalkaloids
  • Salicylates

Carnivore lends itself to intermittent fasting and caloric restriction, both of which have noted health benefits.

You know I’m a fan of self-experimentation. Like any good scientist, you should start by educating yourself. In that spirit, today’s post is a roundup of available research. Use it as a jumping-off point for your own investigations if you are considering going carnivore. As always, I am not providing medical advice here. Please consult your doctors before using carnivore, or any diet, therapeutically.

What Does the Research Say?

Unfortunately, I can’t find any randomized controlled trials looking at carnivore for any health issue. There are a small number of published case studies, and Shawn Baker is currently trying to crowdfund some research. Otherwise, we have to rely on anecdotes and inferences from studies on other related diets (low-carb, high-protein, keto, low-FODMAP, and so on). Anecdotes are important, but they’ll never replace well-designed empirical studies. You can find confirmatory anecdotes supporting any of your beliefs if you find the right subreddit.

I pulled together the best of what I could find for today, but as you’ll see, we still have a lot to learn. The medical conditions included here are ones I’ve been asked about personally or that seem to be popular in carnivore forums. If you’d like me to address another in the future, drop me a comment below.

Carnivore Diets and Autoimmune Conditions

The carnivore diet has been launched into the public consciousness in large part thanks to people like Mikhaila Peterson, who credit carnivore with saving them from debilitating autoimmune illnesses. Using dietary interventions in this context is nothing new. There are more than 100 autoimmune conditions with different etiologies, triggers, and symptoms. What they usually have in common is gut dysbiosis and systemic inflammation. Removing pro-inflammatory, high-glycemic, insulinogenic foods is key to overcoming them.

Many folks are already using low-carb, ketogenic, or gluten-free diets to keep their symptoms at bay. The carnivore diet simply takes those a step further. But does it work? Anecdotally, yes, for some people anyway.

Does Carnivore Heal Leaky Gut?

Many doctors say that autoimmune issues “start in the gut,” since so many autoimmune conditions are characterized by increased intestinal permeability, commonly called leaky gut.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957428/‘>2 Of course, different isn’t always better. I guarantee that an all-Oreo diet will produce some pretty profound changes, too, but I wouldn’t call them favorable.

In this case, though, we have some promising evidence from the Paleomedicina clinic in Hungary. They use a protocol they call the Paleolithic Ketogenic Diet (PKD), which starts out as full carnivore, though patients are ultimately allowed to include a small amount of approved, organic vegetables. Doctors administer a test called the PEG400 intestinal permeability test to all patients and claim great success in bringing patients into normal ranges with their protocol.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1754463/[ /ref] greater fish intake,[ref]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5740014/‘>4 and omega-3 supplementationhttps://www.ncbi.nlm.nih.gov/pubmed/10895373‘>6

A single report from The Medical Journal of Australia in 1964 reports the success of using a high-protein, gluten-free diet to successfully put 20 rheumatoid arthritis patients into remission for a period of up to 18 months.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6592837/‘>8 and a gluten-free diethttps://www.ncbi.nlm.nih.gov/pubmed/31309536‘>10 https://www.ncbi.nlm.nih.gov/pubmed/31634384‘>12 seem to help psoriasis sufferers. Higher intakes of omega-3 fatty acids do as well, which might be expected on a carnivore diet rich in small, oily fish like anchovies and sardines.https://www.ncbi.nlm.nih.gov/pubmed/8219661‘>14 On the other hand, case studies going back decades suggest that high-protein and high-fat diets are not effective and in fact worsen psoriasis symptoms.https://jamanetwork.com/journals/jama/article-abstract/279740‘>16 https://www.ncbi.nlm.nih.gov/pubmed/29605673‘>18

This is one case where I’d tread cautiously. Of course, a quick Google search turns up plenty of people whose symptoms were improved after going carnivore. It can work, and there’s one case study of a patient who was helped by a low-carb, high-protein ketogenic diet.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642427/‘>20 “Residue” is the undigested stuff in food—the leftovers, if you will—that passes through the gastrointestinal tract and gets excreted. Carnivore is an extremely low-residue and low-fiber diet.

Likewise, low-FODMAP diets show considerable promise for relieving the pain and other unpleasant symptoms of IBS.https://pubmed.ncbi.nlm.nih.gov/24830318/‘>22 Remember, FODMAPs are fermentable short-chain carbohydrates that often cause gastrointestinal distress for people with existing GI dysfunction. You won’t find them on a carnivorous diet.

The Paleomedicina team also published a case study of an adolescent boy with Crohn’s disease—a severe form of IBS—who was able to go off his Crohn’s medication after just two weeks on the PKD. After ten months on the diet, ultrasounds of his intestines were normal, and there were no longer markers of intestinal permeability.https://www.sciencedirect.com/science/article/pii/S0166223613000088‘>24 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3285451/‘>26 Therefore, any diet that improves gut health and reduces inflammation is potentially useful.

Psychiatrist Dr. Georgia Ede has become an outspoken advocate of carnivore for depression, as well as other mental health disorders, on these grounds. She also correctly points out that the brain requires fat, including cholesterol, and other nutrients that are much more abundant in animal foods than in plant foods, such as choline, carnitine, omega-3 fatty acids EPA and DHA, and vitamin B12.https://pubmed.ncbi.nlm.nih.gov/25465596/‘>28 Likewise, one study found women who consume less red meat were at greater risk for major depression.https://www.ncbi.nlm.nih.gov/pubmed/17012733‘>30 https://pubmed.ncbi.nlm.nih.gov/19405829/’>32

  • A pilot study showed that when ten participants ate a low-carb (<130 grams per day), high-omega-3, nutrient-dense diet that sounds quite like a typical Primal diet, gum health significantly improved after just six weeks.https://pubmed.ncbi.nlm.nih.gov/30941800/‘>34
  • Carnivore for weight loss

    There’s every reason to suspect that carnivore diets should promote weight loss. If you’ve ever tried, you know it’s hard to overeat protein. Because protein is highly satiating, it tends to lead naturally to caloric restriction.https://www.ncbi.nlm.nih.gov/pmc/articles/pmc2858200/‘>36 https://www.ncbi.nlm.nih.gov/pubmed/16129086‘>38 And of course, we know that ketogenic diets can be great for burning excess body fat.

    Potential Negative Health Impacts of Carnivore?

    Detractors will tell you that carnivore must be bad for your health, what with all that carcinogenic red meat and artery-clogging cholesterol (/sarcasm). Not surprisingly, I don’t put much stock in those arguments. Nevertheless, in the spirit of open-minded pursuit of truth, let’s see what the data actually say.

    Carnivore Diet and Colon Cancer

    I have already debunked the shoddy epidemiological studies that fuel the belief that red meat causes colon cancer, but it’s one of those conventional wisdom “truths” that won’t seem to go away. Sure, don’t eat a ton of processed meats, and don’t eat your red meat on a white-flour hamburger bun alongside fries cooked in rancid oil. But where’s the evidence that a proper nose-to-tail carnivore diet increases cancer risk?

    I can’t find any, but I did find two case studies from the Paleomedicina team that are relevant to this question:

    Emerging research also suggests that ketogenic diets exert anti-tumor effects with certain colon cancers.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5852782/‘>42 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3572016/‘>44 On the flip side, people who follow a high(ish)-protein Atkins diet have lower serum uric acid levels.https://pubmed.ncbi.nlm.nih.gov/25373088/‘>1

    The point is undeniable, though: the expansion in human brain size and intelligence clearly coincided with the rise in meat consumption.

    Now, none of these arguments confirm that we should only eat meat and eschew all plant foods. They do confirm that meat is a natural part of the human diet—and a major part.

    Carnivore Diet Cons

    Detractors point out some potential cons to the carnivore diet. How do they hold up?

    No fiber.

    Detractors say carnivore is unhealthy because it precludes fiber. Is this true?

    For one, it’s not quite true that carnivore diets contain no fiber at all. Animal fiber exists in the form of gristle, cartilage, and connective tissue, and at least in other obligate carnivores like cheetahs, can provide prebiotic substrate that enriches the gut bacteria.https://onlinelibrary.wiley.com/doi/pdf/10.1002/bdr2.1198‘>3 Dr. Ted Naiman has seen this in carnivore patients of his who are otherwise healthy and robust. The best sources of folate on a carnivore diet are liver (which you can’t eat every day because of excess vitamin A) and egg yolks (which must be pasture-raised or follow a specially-formulated diet to be really rich in folate). Eggland’s Best Organic eggs are actually a decent source of folate and readily available if you can’t get pasture-raised.

    There are no great animal sources of magnesium, with the best probably being halibut and cod. Snails and fish eggs are also good sources.

    Meat is a good source of potassium but you have to make sure to consume all the juice. That means eating your meat rare and letting it rest before cutting into it.

    Chris Masterjohn had a great talk with Paul Saladino about the vitamin C/carnivore issue. Chris’ stance was that while a well-made carnivore diet can provide enough vitamin C to avoid scurvy, it might not provide enough vitamin C to be optimal and do the “extra stuff” vitamin C can do. Paul was more skeptical of the need for higher levels of vitamin C. Where both agreed is that a carnivore must eat organ meats (liver and kidney, especially) to obtain enough vitamin C.

    If you don’t eat dairy or bone-in small fatty fish, you risk calcium deficiencies—so consider incorporating them.

    The potential exists for micronutrient deficiencies. Eating a bunch of turkey breast or ground beef won’t cut it.

    No vegetables.

    In previous posts, I’ve supported the idea that plants are important to eat, or at least incorporate as medicinal inputs—in marinades, in teas, in small amounts.

    I stand by that assessment. I still like vegetables. They don’t affect me in a negative way and they taste good. They’re low-carb, provide helpful micronutrients, and reduce the formation of harmful fatty acid peroxides in the digestion process.